parallel scara inverse kinematics hi, i am building a small robotic arm based on the parallel scara design ( some thing like the morgan ) , but i can't seem to find the equations for the inverse kinematics of this design... I know the equations for a serial scara robot.. Does anybody have any idea where i could find them ? Or any links to them thanks https://reprap.org/forum/read.php?185,283327,283327#msg-283327 Thu, 05 Mar 2026 02:51:07 -0500 Phorum 5.2.23 https://reprap.org/forum/read.php?185,283327,850062#msg-850062 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,850062#msg-850062 This is because all the computational algorithmic processes in the function are directed to Cartesian Cartesian coordinate space, for example:

block->millimeters = sqrt(square(delta_mm[X_HEAD]) + square(delta_mm[Y_HEAD]) + square(delta_mm[Z_AXIS]));

This is to calculate the spatial moving distance through the three target coordinates of Cartesian space. If it is replaced by three joint angle values, is this wrong?
The latter algorithm has similar problems, especially the Breasham algorithm in ISR, which is completely an algorithm of Cartesian space. If the value passed to the algorithm is three joint angle values, I think it should be incorrect.
I looked at the code for the marlin 1.1 version and there are similar issues.
I hope that my doubts can be answered, thank you!
My email address: dongxvzhou@gmail.com]]> dongxuzhou Polar Machines, SCARA, Robot Arms Tue, 26 Mar 2019 04:31:35 -0400 https://reprap.org/forum/read.php?185,283327,705228#msg-705228 Ambidextrous SCARA IK https://reprap.org/forum/read.php?185,283327,705228#msg-705228
[gist.github.com]]]> Thinkyhead Polar Machines, SCARA, Robot Arms Mon, 05 Sep 2016 00:27:58 -0400 https://reprap.org/forum/read.php?185,283327,638518#msg-638518 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,638518#msg-638518
thanks

most of the stuff is here
hackaday project
the hardest part is winding the coils so it is not a easy build..]]> ekaggrat Polar Machines, SCARA, Robot Arms Sat, 12 Mar 2016 01:33:22 -0500 https://reprap.org/forum/read.php?185,283327,638101#msg-638101 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,638101#msg-638101
Quote
ekaggrat
Finally done

hackaday

This is so cool ekaggrat, I love the doodle clock.

If I had that on my desk I'd watch it for hours lol. Are the plans to build it anywhere?]]> tomso Polar Machines, SCARA, Robot Arms Fri, 11 Mar 2016 04:44:50 -0500 https://reprap.org/forum/read.php?185,283327,567610#msg-567610 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,567610#msg-567610
hackaday]]> ekaggrat Polar Machines, SCARA, Robot Arms Wed, 07 Oct 2015 05:18:58 -0400 https://reprap.org/forum/read.php?185,283327,283626#msg-283626 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283626#msg-283626
thanks a ton..........

time to build it


]]> ekaggrat Polar Machines, SCARA, Robot Arms Mon, 23 Dec 2013 04:28:59 -0500 https://reprap.org/forum/read.php?185,283327,283599#msg-283599 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283599#msg-283599
reduced:
angB=180-ACOS((L1^2+L2^2-x^2-y^2)/(2*L1*L2))
ang2=90-(ACOS((L1^2-L2^2+x^2+y^2)/(2*L1*RAIZ(x^2+y^2)))+(ATAN(x/y))
ang1=ang2+angB]]> Gomez.Marcos Polar Machines, SCARA, Robot Arms Mon, 23 Dec 2013 03:49:58 -0500 https://reprap.org/forum/read.php?185,283327,283597#msg-283597 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283597#msg-283597
1°- angB=180-Acos((L1^2+L2^2-sqrt(x^2+y^2))/(2*L1*L2))
2°-ang2=Asin(y-(sin(angB*L2)/L1)
3°-ang1=angB+ang2

but even with this the solution fails when angB > 90 degrees ..

so i think this approach might not work]]> ekaggrat Polar Machines, SCARA, Robot Arms Mon, 23 Dec 2013 03:46:30 -0500 https://reprap.org/forum/read.php?185,283327,283581#msg-283581 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283581#msg-283581 ekaggrat Polar Machines, SCARA, Robot Arms Mon, 23 Dec 2013 02:20:13 -0500 https://reprap.org/forum/read.php?185,283327,283580#msg-283580 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283580#msg-283580
EDIT:
its true it have 2 errors one was of writing and the other is bigger lol
I used angB like ang1
give a me a minute]]> Gomez.Marcos Polar Machines, SCARA, Robot Arms Mon, 23 Dec 2013 02:17:54 -0500 https://reprap.org/forum/read.php?185,283327,283576#msg-283576 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283576#msg-283576
thanks for the great solution ... I just couldn't understand what ang B) is? is it ang B ?

assuming it is ang B i plugged the formulas into a excel and it doesn't seem to give a solution ... I think something is wrong....]]> ekaggrat Polar Machines, SCARA, Robot Arms Mon, 23 Dec 2013 01:46:17 -0500 https://reprap.org/forum/read.php?185,283327,283558#msg-283558 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283558#msg-283558
Quote
ekaggrat
hi gomez

thanks for the reply,,, the arm looks like this :



and the working diagram is like this :




i would be very grateful if you could provide me with a solution.. I am not a expert at this things...

thanks again


[imgur.com]
[imgur.com]

We have x,y and we need two angles: one represents the height and the other the angle
first we need distance from x,y to axis :h= sqrt(x^2+y^2)
now angle between arms with law of cosines: angA= (L1^2+L2^2-h^2)/(2*L1*L2)
the angles of the parallelogram always add up to 360: angB=180-angA
calculate real height of arm: hA=sen(angB )*L2
height of arm's joint: hB=y-hA
ang2=asen(hB/L1)
ang1=angB+ang2

so to finish you have to do the next:
1°- angB=180-(L1^2+L2^2-x^2-y^2)/(2*L1*L2)
2°-ang2=asen(y-(sen(angB )*L2)/L1)
3°-ang1=angB+ang2

remember to copy the link finished at .jpg/.png/.* for the images

I like the arm design I'm going to use it at my printer
]]> Gomez.Marcos Polar Machines, SCARA, Robot Arms Sun, 22 Dec 2013 23:51:43 -0500 https://reprap.org/forum/read.php?185,283327,283528#msg-283528 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283528#msg-283528
thanks for the reply,,, the arm looks like this :



and the working diagram is like this :




i would be very grateful if you could provide me with a solution.. I am not a expert at this things...

thanks again


[imgur.com]
[imgur.com]
]]> ekaggrat Polar Machines, SCARA, Robot Arms Sun, 22 Dec 2013 21:14:18 -0500 https://reprap.org/forum/read.php?185,283327,283503#msg-283503 Re: parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283503#msg-283503 Gomez.Marcos Polar Machines, SCARA, Robot Arms Sun, 22 Dec 2013 18:44:09 -0500 https://reprap.org/forum/read.php?185,283327,283327#msg-283327 parallel scara inverse kinematics https://reprap.org/forum/read.php?185,283327,283327#msg-283327 i am building a small robotic arm based on the parallel scara design ( some thing like the morgan ) , but i can't seem to find the equations for the inverse kinematics of this design... I know the equations for a serial scara robot..

Does anybody have any idea where i could find them ? Or any links to them

thanks]]> ekaggrat Polar Machines, SCARA, Robot Arms Sun, 22 Dec 2013 10:30:42 -0500